package org.lee.netty.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;

/**
 * MyServer
 * WebSocket服务器
 *
 * @author dralee
 * @date 2022-01-08 21:40:50
 **/
public class MyServer {
    public static void main(String[] args) throws InterruptedException {
        // 创建2个线程组
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup(1);
        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            ChannelPipeline pipeline = socketChannel.pipeline();
                            //  因为基于http协议，使用http编码和解码器
                            pipeline.addLast(new HttpServerCodec());
                            // 以块方式写，添加ChunkedWrite处理器
                            pipeline.addLast(new ChunkedWriteHandler());
                            /**
                             * 说明：
                             * 1、http数据在传输过程中是分段的，HttpObjectAggregator，就可将多段聚合，
                             * 2、这就是为什么，当浏览器发送大量数据时，就会发出多次http请求
                             */
                            pipeline.addLast(new HttpObjectAggregator(8192));
                            /**
                             * 说明：
                             * 1、对于websocket，它数据是以帧（frame）形式传递
                             * 2、可以看到WebSocketFrame下面有6个子类
                             * 3、浏览器请求时 ws://localhost:7000/hello 表示请求的uri
                             * 4、WebSocketServerProtocolHandler核心功能是将http协议升级为ws协议，保持长连接
                             * 5、通过一个状态码101
                             */
                            pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));
                            // 自定义handler，处理业务逻辑
                            pipeline.addLast(new MyTextWebSocketFrameHandler());
                        }
                    });
            ChannelFuture future = bootstrap.bind(7000).sync();
            System.out.println("服务器开启..");
            future.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}
